A tow hitch is a device that attaches to a passenger vehicle, such as a car, truck or sport utility vehicle (SUV). The tow hitch serves as an attachment point, allowing the passenger vehicle to securely connect to and tow any number of wheeled attachments, including a recreational vehicle (RV), a travel trailer, a flat bed trailer, or another passenger vehicle, for example. The trailer hitch is typically bolted or connected to the chassis of the passenger vehicle to provide a secure point of attachment and to enable the passenger vehicle to safely tow large loads.
Trailer hitches generally come in two varieties: fixed drawbar and receiver-type. A fixed drawbar trailer hitch consists of a single assembly with a fixed tow attachment point, such as a trailer ball or an attachment point for a trailer ball. Fixed drawbar trailer hitches are typically designed for a single purpose and single configuration and, as such, are not configurable in terms of height or attachment options. For example, a fixed drawbar trailer hitch used to tow a boat, which requires a specific hitch connection height, cannot be used to tow a horse trailer that requires a different hitch connection height.
A receiver-type trailer hitch typically attaches to the chassis of the passenger vehicle in the same manner as a fixed drawbar trailer hitch. A receiver-type hitch, however, contains a standard attachment point, or receiver, that allows the interchange of a variety of different attachment options, in addition to a trailer ball. For example, in order to tow different trailers requiring different hitch connection heights, a different tow attachment providing the appropriate rise or drop to achieve the required hitch connection height mates with the receiver. The receiver is typically a square sleeve of a standard size that accepts an attachment. A pin slides through a set of holes in the receiver and a matching set of holes in the attachment to secure the attachment.
Trailer hitches in North America are classified by the size of the trailer they can safely tow. Two values classify trailer hitches: the carrying weight and the tongue weight. The carrying weight is the weight of the trailer itself. The tongue weight is the force exerted downward on the hitch by the trailer at the attachment point.
The standard classification for trailer hitches is defined by the Society of Automobile Engineers (SAE). Common classifications include Class I, II, III, IV, and V. Carrying weight ranges from 2,000 lbs for Class I to 12,000 lbs for Class V trailer hitches. Similarly, tongue weights range from 200 lbs for Class I to 1,200 lbs for Class V trailer hitches. For receiver-type trailer hitches, the size of the receiver typically varies by class and is determined by measuring the receiver opening. Classes I and II typically have a 1.25 inch receiver (an opening of 1.25 inches measured in each direction). Classes III, IV, and V typically have a 2 inch receiver, although Class V hitches may a 2.5 inch receiver.
In addition to serving as an attachment point for towing, receiver-type trailer hitches may attach a variety of accessories for other purposes. For example, at times, the need arises to transport one or more bicycles by passenger vehicle. For most vehicles, such as cars, it is not desirable to transport the bicycles in the interior of the vehicle. Instead, a bicycle mount attachment appropriately sized and adapted to couple with a receiver-type trailer hitch can be used to securely transport the bicycles on the outside of the car. Similarly, a receiver-type trailer hitch can be used mount a gas grill specially adapted to couple with a receiver-type trailer hitch. Such an arrangement allows both for transportation of a full size gas grill, which would otherwise be difficult to cleanly and safely transport, but also provides physical support when operating the grill, which obviates the need for a separate grill stand.
Despite the flexibility of receiver-type trailer hitches to accept a wide variety of attachment accessories, one difficulty is that each accessory is specialized for a specific purpose and each accessory is typically bulky. This generally limits the use of accessories on a given trip because extra accessories are generally hauled within the vehicle, taking up valuable space.
Vehicles equipped with receiver-type trailer hitches are commonly used for many activities including tailgating. Tailgating is a common social activity in the United States and involves gathering on or around the open tailgate of a vehicle, typically a pickup truck, SUV, or van, but also cars, RVs, and busses. As tailgating is generally an outdoor activity, rain and other poor weather is usually a concern. In cases of poor weather, tents or umbrellas provide shelter for the tailgating participants. One problem, however, is providing a secure means of supporting the tent or umbrella.
In addition to tailgating, pickup trucks are often used for a variety of purposes, including hauling and transporting anything from dirt to furniture. Pickup truck beds are typically raised off the ground to such a degree that it is not easy to step into the truck bed. Instead, to enter the truck bed, one must typically climb into the truck bed using an open tailgate, or climb over the side wall of the truck bed, or climb over the closed tailgate.
It would, therefore, be desirable to have a single apparatus capable of being attached to a standard receiver-type trailer hitch that would perform multiple functions, such as serving as an adjustable towing attachment, a bike carrier mount, a step for entering the pickup truck bed, and an umbrella holder.